Deformation Temperature Dependence of Mechanical Properties and Microstructures for a Novel Quenching—Partitioning—Tempering Steel

The present investigation on a designed high strength Fe-0.25C-1.48Mn-1.20Si-1.51Ni-0.05Nb （wt%） steel treated by a novel quenching-partitioning-tempering （Q-P-T） process was focused on deformation temperature dependence of mechanical properties and microstructures. The results indicate that the Q-P-T steel deformed at various deformation temperatures from -70 to 300 ℃ exhibits superior mechanical properties due to excellent thermal stability of retained austenite. The microstructural characterization by transmission electron microscopy （TEM） reveals that the high strength of the Q-P-T steel results from dislocation-type martensite laths and fcc NbC carbides or/and hcp ε-carbides precipitated dispersively in martensite matrix, while excellent ductility is attributed to the significant transformation induced plasticity （TRIP） effect produced by considerable amount of retained austenite. The relationship between mechanical properties and microstructures at different deformation temperatures was clarified.

Recent advances in fire-retardant carbon-based polymeric nanocomposites through fighting free radicals

Polymeric materials are ubiquitously utilized in modern society and continuously improve quality of life.Unfortunately,most of them suffer from intrinsic flammability,significantly limiting their practical applications.Fundamentally,free-radical reaction is a critical“trigger”for their thermal pyrolysis and following combustion process regardless of the anaerobic thermal pyrolysis in the condensed phase or aerobic combustion of polymers in the gaseous phase.The addition of free radical scavengers represents a promising and effective means to enhance the fire safety of polymeric materials.This review aims to offer a state-of-the-art overview on the creation of fire-retardant polymeric nanocomposites by adding fire retardants with an ability to trap free radicals.Their specific modes of action(condensed-phase action,gaseous-phase action,and dual-phases action)and performances in some typical polymers are reviewed and discussed in detail.Following this,some key challenges associated with these free-radical capturers are discussed,and design strategies are also proposed.This review provides some insights into the modes of action of free radical capturing agents and paves the avenue for the design of advanced fire-retardant polymeric nanocomposites for expanded real-world applications in industries.

GLUCOSIDASE INHIBITORY ACTIVITY AND HPLC ANALYSIS OF THE FLAVONOIDS OBTAINED FROM IMPATIENS BALSAMINA L. OF DIFFERENT REGIONS

A simple and efficient HPLC method was developed for quality analysis of flavonoids from Impatiens balsamina L.(IBL)flowers,which were collected from Xingjiang,Anhui,Henan,and Hubei provinces in China.The flavonoids substances in IBL were determined by HPLC through methyl alcohol ultrasonic extraction.A mixture of

THE EVALUATION METHODS OF VELVET ANTLER AND THE DETERMINATION OF NUCLEOSIDES AND STEROID HORMONES IN DIFFERENT PARTS FROM SIKA DEER AND RED DEER

Velvet antler is an important and precious traditional Chinese animal medicine,and was used for strengthening the kidney,anti-fatigue,improving sexual function and so on.But the evaluation methods of velvet antler and the scientific evidence for the use of antler is insufficient.Materials and Vacuum freeze drier was used for dehydration of the fresh antler at-60.,6 pa for 24 h.